Battery Vehicle Society

I am not 100% sure on the chemistry of my particular batteries, but I know they are the earlier Thundersky Batteries.

charging a thundersky to 4.35 will result in very rapid cell death, from what i've read and seen (don't ask me how i know, but it had something to do with bypassing the bms and overcharging an old headway pack)

my batteries look like these ones

http://3xe-electric-cars.com/images/doc ... celist.pdf

This is a Citroen C1 Ev'ie battery pack on the bench. You can see the main part of the pack which goes under the bonnet joined to the smaller part that goes under the rear of the car.

Well with the car havig sat barely used for a few days in this nice cold spell I have noticed some big old voltage drops when I drive the car hard. I have been having to drive it gently to keep the voltage from sagging too far. It'll get a good run today so I am hoping to get a good cycle on the battery pack and hopefully manage to warm it up a bit.

Not to worry, my pack does the same. Cold weather hurts performance and range unless you have some sort of battery heating system. It's not a problem for me as I have enough reserve capacity in the pack that the reduced range doesn't cause me a problem.

I have more than enough range for the trips I make so the cold weather isn't too much of a problem. There are a couple of short hills on one route and typically there is a set of traffic lights at the bottom of one of them but I am not to worried about making a slow start up the hill.
I do notice a big difference in voltage sag at the end of a day if the car has been used a few times and been on charge in between so the pack must warm up intenally because the voltage sag is much less come the end of a day - as much as a 5 volt difference from the start of the day.
I have also had a new heater fitted as the previous one was a bit weak and I love the fact that I can pop out on a frosty morning and turn the heater on 10 minutes before I leave and the car is toasty warm when I go back out to it.